1. Field of the Invention
The present invention relates to gyroscopically stabilized apparatus, and particularly to gyroscopically stabilized apparatus for aiming an instrument at a target object.
2. Description of the Prior Art
Although the invention has broad application to the stabilization of practically any instrument carried by a vehicle, it has particular utility in stabilizing a helicopter mounted camera system for filming motion pictures. Therefore, the emphasis in the ensuing discussion on helicopter camera systems should be understood to be merely exemplary.
In my U.S. Pat. Nos. 3,352,521 (Universal Mount) and 3,467,350 (Vibration Damping Mount), systems were disclosed for steadying a helicopter mounted camera during manual tracking of a target object, and for substantially isolating the camera from helicopter induced vibrations. A need has since developed for an effective remote controlled stabilized platform for supporting the camera.
Such a platform is disclosed in U.S. Pat. No. 3,638,502, issued to Leavitt et al, and a related system is disclosed in U.S. Pat. No. 4,989,466, issued to Goodman.
Both of these prior art systems disclose a stabilized gyro platform and a camera platform which are both housed within a fairing shaped like a dome or sphere. The camera platform is supported by the gyro platform for movement within the sphere about a tilt axis. The gyro platform is coupled to a universal joint which is suspended from a vertical support post. This enables the helicopter to pitch and roll relative to the level and stable gyro and camera platforms. However, the degree of pitch and roll is limited because the vertical support post impacts against either the gyro or the camera itself.
The support post extends from the internal universal joint to a point located exteriorly of the sphere, where it is connected to a support arm projecting from the side of the helicopter.
The sphere is rotated by a servomechanism in response to a position sensor to maintain alignment between a window in the sphere and the camera lens during panning and tilting of the camera platform. Coordination of the operation of the camera platform and the servomechanism controlling the window location must be precise, introducing a degree of undesired complexity into the apparatus.
Additional complexity is presented by the internal location of the support post. The helicopter can only pitch and roll to a predetermined extent. Beyond that the camera or gyro platforms strike the post and the gyros will uncontrollably precess or tumble. Further operations then have to wait until the gyros are erected or caged to stabilize the gyro platform.